Fix incorrect call to isMechanismPermitted (#835)

This fixes build failure introduced in f3c0156

Author: bukka

src/lib/SoftHSM.cpp

@@ -2455,7 +2455,7 @@ CK_RV SoftHSM::AsymEncryptInit(CK_SESSION_HANDLE hSession, CK_MECHANISM_PTR pMec
 		return CKR_KEY_FUNCTION_NOT_PERMITTED;
 
 	// Check if the specified mechanism is allowed for the key
-	if (!isMechanismPermitted(key, pMechanism))
+	if (!isMechanismPermitted(key, pMechanism->mechanism))
 		return CKR_MECHANISM_INVALID;
 
 	// Get key info